Dissecting the Relationship between a CHD3 Chromatin Remodeler and the Repressive Epigenetic Mark H3K27me3 in Arabidopsis

点击翻译按钮获取中文摘要

Intellectual Merit: The long-term objective of this project is to understand how the CHD3 class of ATP-dependent chromatin remodeling factors contributes to regulation of gene expression and developmental identity. In animal model systems, CHD3 proteins have been shown to act through a multisubunit complex (Mi-2/NuRD) in combination with histone deacetylase to repress transcription of genes that play a critical role in differentiation and development. In the plant model system Arabidopsis thaliana, the CHD3 gene, PICKLE, also represses expression of genes and plays an important role in developmental transitions. However, there are two key differences between PICKLE function and CHD3 function in animals. First, PICKLE does not appear to function in the plant equivalent of Mi-2/NuRD. Second, PICKLE appears to operate through formation of the repressive chromatin mark, trimethylation of histone H3 lysine 27 (H3K27me3). This histone modification is known to play a critical role in gene repression in both animals and plants, but is not directly regulated by CHD3 proteins in animals. To understand how PICKLE regulates gene expression, this project will take advantage of powerful genetic, biochemical, and developmental tools to explore how CHD3 proteins contribute to chromatin structure and gene expression. Specifically, experiments will be aimed at characterizing the remodeling activity of recombinant PICKLE protein and examining the contribution of various conserved protein domains to PICKLE function in vitro and in vivo. The results will shed light on new mechanisms of action for CHD3 remodelers that are anticipated to be generally applicable to all eukaryotes.Broader Impacts: The planned research aligns well with the education mission of NSF. The project will build on a long tradition of engaging students in research by providing both undergraduates and graduate students with opportunities to carry out research. This will provide the students with a solid foundation in science associated with chromatin biology, model systems, and genome-based approaches. Finally, the PI will continue to synergize his experiences in the lab with those in the classroom and thereby provide a more meaningful educational experience to students.